Rotary couple pump



June 17, 1941. w. w. DAvlDsoN ROTARY COUPLE PUMP Filed Aug. 4, 1940 4 Sheets-Sheet 1 MW /ZGW June 17, 1941. W, w DAVlDsQN 2,246,271

ROTARY COUPLE PUMP (c YL wafe) June 17, 1941. w. w.- DAVIDSON ROTARY COUPLE PUMP Filed Aug. 4, 1940 4 Sheets-Sheet 3 June 17, 1941. w. w. DAVIDSON ROTARY COUPLE PUMP Filed Aug. 4, 1940 4 Sheets-Sheet 4 Patented June 17, 1941 UNITED vSTATES Prin-:NTl OFFICE 2,246,271 ROTARY` COUPLE PUMP William Ward Davidson, Evanston, Ill. Application August 4, 1940, 'Serial No. 351,360

40 Glaims.

Theoretical advantages of rotary couple pumps have long been known. By rotary couple pump is meant one in which an outer cylinder and an inner core (often called the piston or rotor) both rotate about their own centers but in eccentric relationship tcform a crescent-shaped pumping chamber between them. End walls are of course provided to close the sides of the pumping chamber; r

One of the advantages of such pumps is their freedom from vibration if properly made. Both the outer cylinder and the innercylindrical core can of course be accurately balanced and, since each is rotating about its own center, it is obvious that there need be no vibration due to centrifugal force. with the two members rotating approximately in unison there is relatively little wear between the parts,

Because oi` these advantages there have been tical rotary couple pump. Prior t my invention it is believed that all such attempts have been unsuccessful, at least for pumping gas with which the present invention-is chiefly concerned. There are several features, which are keys to making such a rotary couple compressor successful. It is believed that each of the prior art rotary couple pumps lack at least one of these -key features, and most of them in fact lack more than one. It is not intended to imply that every one of these key features is absolutely essential to a successful pump, especially since ways may be found to get along without each of them, and some affect the life of thepump more than its operativeness or efficiency. However, tests have shown that pumps embodying these fea- Another advantage is that almost innumerable attempts to produce a practures are substantially more efficient than the l of a rotary, couple pump, although vthe inner corev is often called the piston, the blade really functions as a piston by sweeping through the crescent-shaped chamber and forcing the gas out chamber pressure.

" members, unless this path is 'lled with oil.

the pressure backing up the oil is not sufficient,

ahead.of it through the discharge port While drawinggas in behind it through the inlet port. If the blade is not sealed to the endwalls, gas can leak from the high pressure side of, the blade to the low pressure side and thus destroy the eiciency of the pump. The best way of sealing the blade is to have it clamped 'tightly between the end walls, which close the ends of the space between the cylinder and the inner core.

3. Thrust. bearings should not be relied on for the clamping pressure-Both end walls should be rigidly secured to lone of the pump members, either the outer cylinder or the inner core. In being rigidly securedto a pump member, the end walls should have a ground t therewith so as to be sealed thereto,

4. TheI blade, being rigidly clamped between the end walls, should also be rigid with thev b'e kept ,filled withbiladfiacent the crescentshaped working chamber, 'at least throughout the zone of high pressure therein-Mere lubrication is not enough. In order for oil-seal to be kept in this space, the oil must be fed to the clearances at a pressure in excess of the working An oil-seal between the chamber and the shaft is not enough. The pressure from the high pressure sectidn of the chamber can get to the low pressure section of the chamber by passing through one of the clearance spaces in question by a short\'path adjacent the point of tangency between the two pumping the oil will be blown out, and the gas will -escape to the low pressure section.

6. A rocker or equivalent device should be provided for the blade-The end of the blade which is'not rigid with one member should not merely bearagainst the other member but should be sealed yto itas by a cylindrical slotted rocker, which permits a sliding rocking movement of the blade with respect to the member by which the rocker is carried.

.7. There mus? be som'e escapement of oil into the pumping chamber to seal the point of tangency, or, more. accurately, the line of tangency. The pump is, of course, designed with a very minute clearance between the outer cylinder and v2,246,271 -the core, land so very little oil-is required for th h across these paths if lthe oil seal is obtained in some other way. Pressure on the oil in the' end wall clearances can be high enough to seal these paths since the movement of the parts helps to carry the oil into or through the clearances.

9. The oil pressure should be as much higher than the pump chamber pressure as may be necessary to effectively seal the clearances without being wastefully high- The most convenient method of getting this result at present appears to have grooves carrying oil around the clearances near the pump chamber and to control the pressure automatically by a vent having a restricted pressure relief orifice between the oil passages and the dome or discharge. passage of the pump. With a constant oil pump speed, such a relief orifice ensures a predetermined relationship of the oil pressure in excess of the dome or head pressure.

10. For various reasons a rotary tangential pump is preferred-A positive displacement pump of some type which dependably pumps a predetermined amount of oil with each cycle appears to be important. It has a certainty of oil circulation which no other pump has and coopcrates satisfactorily with the pressure relief orifice. Furthermore, the pulsating nature of the discharge of a tangential pump can be utilized of a rotary couple pump whose movement is opposed by the pressure of the compressed gas. 1f the blade were driven by the rocker, there would be a diillcult friction problem because the entire force of compression would have to be ex- 'erted through a sliding t.

-13. The driving connection should be to the outer cylinder rather than `iust to the inner core. There are various reasons for this, but for the present it may be noted that this makes the best use of the outer member as a iiywheel.

14. The blade should always project` into the rocker at least`as far as the axis of the rocker.- This is especially true when, as will usually if not 'always bathe case, the blade drives the rocker and the member by which the rocker is carried, If the blade, in its retracted position, does not extend to the axis of the rocker, its driving force will tend to cant the rocker an greatly increase the frictionv and wear.

15'. The bearings'should support the cylinder and rotor without any canting; and particularly without any canting with respect to each other, and the bearing meansy should be adequate in size to withstand the pressures involved. The lack of cant is accomplished in general by providing bearing means' on both sideslof the center of each ofthe pumping members.

16. There should be as little re-ezpansion as possible.-Any pockets which communicate with serves to separate and conserve this oil.

the pump chamber, and from which the gas cannot be expelled by the pumping action, represent a loss of efficiency because of the fact that'the.

gas in these pockets expands into the pump chamber when they pass into the intake side thereof. Little, if any, of the work done in compressing the gas into the pockets is recovered, and there is that much less gas thatis expelled into the dome or storage tank.

17. There should be a gas-tight dome surrounding the pump-Since a little oil is necessarily forced into the working chamber for sealing and is discharged with the gas, the dome also useful in connection with the automatic regulation of oil pressure. See Paragraph 9 above.

18. The external rotational friction should be minimized-This is accomplished by avoiding external protuberances and having the rotating cylinder positioned entirely above the oil level.

This application is a continuation in part of my copending application Serial No. 36,877, illed Aug. 19, 1935, and through it and application Serial No, 62,874 relates back to application Serial No. 688,169, filed September 5, 1933 and .y Serial N0. 591,087, led February 5, "1932. The

present application is to serve as the basic patent on the inventions common to these and other related applications.

According to the preferred form of the present invention, which form is illustrated in the drawings, every one of these numerous requirements is met. Additional advantages and objects of the invention will be apparent from the following description and from the drawings, in which:

Fig. 1 is a vertical sectional view of the pump taken, for the most part, approximately on the line I--I of Fig. 2, but partly broken away to show the rocker and blade, and with other slight departures from the main plane of the section for the sake of clarity of illustration.

Fig. 2 is a horizontal sectional view approximately on the line 2-2 of Fig, 1.

Fig. 3 is a` fragmentary side view of the rotating structure, showing particularly the arrangement of the blade and the discharge check valve in the outer cylinder.

Fig. 4 is a horizontal sectional view, taken on the line 4 4 of Fig. 1, and illustrating the oil Dump.

Fig. 5 is a fragmentary view taken practically on the line 5-'5 of Fig. 1, illustrating an end face of the core and showing the blade beyond the point of tangency. l

Fig. 6.is a. view similar to Fig. 5, but showing the parts after they have rotated Fig. 7 is a fragmentary sectional perspective view taken approximately oon the line 1-1 of Fig. 6 and showing the oil grooves for the rocker and blade.

. art.

Fig. 8 is a vertical sectional diagrammatic view of a. modied form of the invention.

A preferred form of the invention has been` chosen 'for illustration and description, in compliance with section 4888 of the revised statutes, and a modification has been shown, but persons skilled in the art will readily perceive other means for accomplishing the same results, and the claims are therefore tobe construed as broadly as possible, consistent with the prior As seen best in Fig. 1, the pump includes a combined housing and frame structure Il, within which is positioned the main pump I2. 'I'he It ispump includes an outer cylinder I3 and an inner cylindrical core member or piston I4, both of which may be called pumping members and each of which rotates about its own center.

Pumping action As seen best in Fig. 2, the cylinder I3 and core I4 are in tangential relationship. The point or line of tangency is seen at I6. Because both the cylinder and core are rotating about their own centers, this point of tangency does not move. Since the core I4 is slightly smaller than the cylinder I3, a crescent-shaped chamber I1 is formed between them, this chamber being called the working or pumping chamber. A blade I8 is sealed to both the pump members I3 and I4 so as to divide the working chamber I1 into intake and discharge sections. An intake port I9 communicates with the intake section, and a discharge port 20 communicates with the discharge section of the working chamber I1.

The blade I8 Irotates with the cylinder I3 and the core I4, and in eiect sweeps through the crescent-shaped chamber I1 in a clockwise direction, as indicated by the arrow in Fig. 2. As the blade leaves the point of tangency it draws air or gas in behind it through the intake port I9.

As seen in Fig. 2, the incoming gases have been drawn in behind the blade to fill the lower half of the crescent-shaped working chamber. As seen in Fig. 6, they have been drawn into nearly all of the crescent-shaped working chamber. During the next revolution the blade will sweep through this chamber again and force all of this gas through the discharge port 20, at the same time drawing in more gas behind the blade through the intake port I9. 'Ihe blade I8 is thus in effect a continuously operating piston, since it is continuously pushing gas ahead of it, either compressing it or forcing it through the discharge port 20, and is continuously drawing gas in behind it, except, of course, at the moment it is passing the point of tangency. The term blade is preferred to fpiston because it is more common to speak of the core I4 as the piston. The blade is also sometimes called a vane Intake structure The intake port I9, is, in its preferred form, a series of ports, as seen in Fig. l. These ports communicate at their inner ends with an annular channel 23, formed partly by an annular groove in the core I4 and partly by an approximately mating annular groove in the shaft center 24.

The shaft 24 is provided with a longitudinal bore 26 which communicates with the channel 23 through passages 21 which are staggered circumferentially and longitudinally of the shaft 24 so as to have substantially no weaking effect on the shaft. The air or gas enters the bore 26 through an intake connection 28 which may be provided with a check valve. Any check Valve may be used but the illustrated check valve includes a seat 29 which is preferably an insert and may be sealed by a rubber washer, a disc 3I having a serrated edge, and a coil spring 32 normally urging the valve disc 3| against the seat 29, except when it is opened by th"`sucv tion within the bore 26. The spring 32 bears against a perforated and externally threaded nut 33 through which the gas passes to the bore 26. This intake check valve will ordinarily be omitted in a simple air compressor.

Discharge structure ited by a second spring 39. This entire valve mechanism may be secured in a recess 4I in the cylinder I3 by screws 42. Of course, any other satisfactory check valve may be used.

There are two advantages in countersinking the check valve mechanism in the recess 4I. First is the advantage of streamlining the rotating cylinder I3 so that there will be less air resistance to its rotation. It will be observed in this connection that, except for the slight irregularity in the vicinity of the check valve, there are not projections beyond the circular cross section of the cylinder. Because of this fact and because of the fact that it is located entirely above the oil level, there is very little resistance to its rotation. v

A more important advantage of the countersinking of the check valve in the recess 4I is that it shortens the length of the discharge port 20. The Adischarge port 20 is a pocket which retains a certain amount of the compressed gas and permits it to re-expand after the pocket has passedv the point of tangency. This re-expansion is wasteful because the energy used in compressing the gas cannot be recovered and furthermore it interferes with the volumetric etliciency of the pump since-there is that much less gas discharged during each cycle of the pump than if the pocket were not present. -By coun tersinking the check Valve to the point where the walls surrounding the port 20 are as thin as safety will permit, the re-expansion volume is reduced to a minimum, Itwill be observed that,

except for the very minute pockets adjacent the blade I8, this port 20 is the only re-expansion pocket. To the extent that these minute pockets are lled up by oil, the re-expansion is reduced still further. ,The volumetric efliciency of the pump is therefore extremely high.

The gas discharged throughthe port 28 flows into the chamber formed by the housing or dome II which serves as a storage reservoir and oil separator. The compressed gas then flows to the point of use, or to the condenser in the case of refrigeration, through pipe 44.

The recess 4I will preferably be covered over with a perforated plate, not shown, for the purpose of streamlining. Likewise, the holes through which the screws 46 are inserted will be plugged for the same purpose. In both instances the cover or plug should be substantially flush with the surface of the cylinder.

Outer' cylinder construction End walls The end walls for the cylinder comprise a lower head or end plate 41 (Fig. 1), and an upper head or end plate 48. is secured directly to the cylinder by suitable bolts screwing into the cylinder I3. The upper The lower end plate 41 end plate 48 is clamped between the cylinder I3 and a cap or outer head 49 by suitable bolts screwing into the cylinder I3. Of course, the mating surfaces of the cylinder I3 and the end plates 41 and 48 are ground as are all sealing surfaces. It will be observed that because the bolts screw into the cylinder and secure both end plates firmly to the cylinder, the structure forms a rigid unit so that no internal pressure can spread the end plates apart or exert a spreading force through them to end thrust bearings. Furthermore, the end plates are-thus positioned with absolute certainty and rigidity at the proper distance apart to provide the predetermined operating clearances between the insides of the end plates and the ends of the core member I4. These results can only be secured by having both end platesrigidly secured to the same pump member, or in some similar and equivalent way.

Bearings To preventcanting of the cylinder it is supported by bearings at both ends thereof. The head k41 has an integrally formed hub or hollow shank I in which may be pressed or otherwise secured a bearing ring 52 which runs o n a bearing hub extension 53 formed integrally on the lower support plate 54 forming a part of the housing or frame II. The upper head or cap 49 is provided with a shank extension 56 which runs within a bearing surface 51 formed by the upper supporting member 58 of the dome or frame II. The shank 56 is the driving shank, being extended through the support member 58 in the form of a drive shaft 59 to which a motor is suitably connected. The motor may be supported by the extensions fragmentarily shown at 6I. In extendingY through the upper support member 58, which in this instance is part of the gas-tight dome, the shaft must have a gas-tight seal therewith, and such a seal has been illustrated in Fig. 1. The exact nature of the seal is not important and this one may be regarded as diagrammatic. Any satisfactory seal may be used. It may be briefly noted that the stationary seal ring 62 is sealed to the dome member, and the running seal ring 63 is sealed to the shaft 59, the ring 63 preferably being formed of carbon so as not to require lubrication.

Accurate axial alignment of the bearing surface- 51 with the outer bearing surface of the stationary bearing hub 53 is ensured by a snug telescopic t of the end support members 54 and 58 with the cylindrical dome member 64, as seen at 65, and by the use of a relatively hard thin type of gasket available on the market. Of course even with more yielding gaskets accurate alignment could be obtained by tightening the securing bolts for the frame parts with suflicient care. Without the preferred type of gasket, however, mass production considerations would make the provision of a frame having metal to metal contact between its parts desirable, a 'separate or partially separate external dome being provided, as in Fig. 8.

,The core is likewise supported in a manner to prevent its canting by being journaled on a rigidly mounted shaft, the bearing surfaces being adjacent both sides of the core. As seen best in Fig. 1, the shaft 24 is provided with an annular shoulder 66 which is drawn against a matching shoulder of the lower stationary hub 61. The main portion of the shaft fits snugly in this hub 61, and has its end threaded and provided with a nut 68 for drawing the shoulder 66 firmly against the hub 61. As seen from the drawings,

vshaft 24 is eccentric with respect to hub 61.

At its upper end the shaft 24 has an eccentric bearing stud 69 which is concentric with the shaft 59 so that bearing means may be provided between these two shaft members. In its preferred form the bearing means comprises the ball-bearing unit 1I disposed as clearly illustrated in Fig. 1. It will `be observed that although the shaft 24 is relatively long and slim, it is supported at both ends and hence will not undergo any appreciable flexing.

The core I4 is journaled on the shaft 24 as clearly seen in Fig. 1. To obtain adequate bearing surface in spite of the thinness of the shaft 24, the core I4 is provided with extended hubs or hollow shanks 13 and 14. It is thus seen that the core I4 may have a length of bearing considerably longer than the width of the pumping chamber. This extra length .may not be necessary for low pressures but it is very desirable for higher pressures and higher speed.

In addition it will be noted that stationary bearing hub 53 forms an external bearing for the lower hollow shank 14, thus-further increasing the bearing area for the core.

The upper head 49 is preferably formed of steel, the preferred material of bearing ring 52, and hence no such ring is needed for the bearing surface 51. Both matching bearing surfaces of support members 54 and 56 are nickel-iron. It may be noted here that the shaft 24 is steel and the core I4 nickel-iron to provide the desirable bearing combination.

In view of the fact that the bearing surface 51 does not have to withstand the pumping pressure, a smaller bearing might be used here. The pumping pressures between the upper end of the cylinder I3 and the upper end of the core I4 are taken up at least primarily by the ball-bearing unit 1 I.

Rocker Although the blade I8 has a rigid sealed t with the cylinder I3, it is important for it to have also a sealed t with the core I4. This is preferably provided by a one-piece cylindrical rocker 16, seen best in Fig. 2. The rocker 16 has a snug t with the core I4 and is provided with a slot 11 into which the blade I8 slides snugly. As seen in Fig. 2, the blade, even in its most retracted position,

. extends at least to and preferably beyond the axis of the rocker 16 so that there will be no tendency for the blade to cant the rocker so as to make the slot 11 out of alignment with the blade I8. The rocker 16 is of the same length as the width of the core I4. The blade I8 is of the same length as the cylinder I3 so that it is clamped rmly by the end plates 41 and 48 having a sealed fit therewith. i Oil pump The oil pump is positioned immediately above the annular projection 66 in Fig. l and is best seen in Fig. 4, which shows the parts in section and on a larger scale. The stationary hub extension 53 forms the cylinder of the oil pump. A freely rotatable ring 8| forms the other pumping member, often called a piston or rotor and corresponding somewhat to the core of the main pump. The ring 8I is in tangential relationship with the cylinder or hub 53. In this instance the point of tangency is not stationary but rotates under the influence of the eccentric cam 82 formed by the lower end of the bearing shank 14 of the main core I4. A blade or abutment 83 is provided for the pumping ring'8l by a spring 86 which ineiective to deliver oil directly to the gas pump on starting but is not hig'h enough to submerge a substantial part of the rotating cylinder of the gas pump. The oil level may be high enough to submerge the oil pump, as shown in Fig. 8. The intake port 88 is provided with a passage 9| communicating with the oil reservoir. Oil ilows in through this passage and is pumped by the planetary movement of the pumping ring 8l out through the discharge port 89.

Lubrication of bearings As best seen in Fig. 1, the discharge port 89 communicates with an upwardly extending passage 92 (Fig. 1) in the hub extension 53. A passage 94 extends radially therefrom andl communicates with an annular oil groove 95 formed in the inner wall of bearing ring 52. This groove distributes oil all around the running surface of' the bearing ring 52 and its mating bearing surface, and a vertically extending groove may be provided if desired, although the pressure of the oil is believed to be enough to distribute the oil without such a groove, The annular groove 95 communicates with a passage 96 in the lower head 41 which in turn communicates with a passage 91 extending upwardly through the cylinder I3. This passage in turn communicates with a passage 98 formed in the upper head 48 which opens into a bearing chamber 99 in which the ball-bearing unit 1I is located. The oil ilows through the ball bearings to a clearance space Another passage |09 communicates with chamber 99 for supplying oil to the upper bearing surfaces for the core I4, a longitudinal (spiral) Vgroove again preferably being provided.

Oil sealing One or more channels III and III' in the op posite faces of the core I4 communicate with the annular recess |06 and with the chamber 99 respectively, and carry oil out to identical annular grooves II2, the upper of which is seen best in Fig. 5. It is at present preferred to deliver oil to grooves'IIZ near their leading ends as by grooves III so that the inertia of the oil will tend to help its flow through the grooves II2. Channel I I.I could be omitted. One or more passages II3 are drilled vertically through the core I4 and connect the two grooves IIZ together. It will be observed that any two of the passages II3 or 91 may be omitted, but at present it is preferred to provide at least one passage I I3 and the passage 91 as a matter of precaution in case The upper end of the passage 92 communicates with an annular recess |06 onthe inside ofthe bearing hub 53. A radial passage |01 communicates with the annular passage |06 and carries oil to the bearing surfaces between the core I4 and the shaft 24. Because of the length of thesebearing surfaces a longitudinal oil groove |08 is preferably provided. For the sake of clarity, all of the oil grooves longitudinal of the bearings I -have been `shown as if parallel with the-axes.

In fact, they would be spiraled so as not to decrease the bearing area appreciably along one li'ne.

one should become obstructed and to be sure that there is plenty of oil at the upper end of the pump. 'I'he purpose of these annular grooves is to seal the infinitesimal end clearances between the core I4 and the end plates 41 and 48. Although there may have been attempts before this invention to seal these end clearances, it is believed that such attempts have not been successful. In most instances at least there has been a failure to recognize the requirements for an effective seal. It is not enough to prevent the gases from flowing axially from the pumping chamber to the shaft where they could leak through the bearings. It is equally important, or even more important, to seal these spaces so thoroughly that gas cannot leak around the point of tangency from the high pressure section of the pumping chamber to the low pressure section by passing through these end clearances. Furthermore, it is not enough to make a small volume of Oil flow indiscriminately from near the shaft to the periphery point of tangency so as to completely block the path of gas flowing from one section of the pumping chamber to the other.

It may not be enough to merely have the pressure in the groove II2 high enough to prevent the oil in this groove being blown back by the gas. It is preferred to have it a little higher than this so that there will actually be a slight ow of oil. The flow of oil may be very small and still be enough to prevent the oil from being blown in a direction perpendicular to the radius so as to be blown out into the low pressure section by a gas escaping from the high pressure section; Of course, this theory is not necessary to the disclosure of the invention, but tests have indicated that unless the oil pressure is appreciably above the head pressure against which the pump is working, the efficiency of the pump is greatly decreased. The amount that the oil pressure shall be above the head pressure for maximum efficiency depends on several factors, the chief of which is probably the longest distance the oil has to flow through the minute clearances to get to the point which it seals. With the previous form of pump, tests have indicated that about ten pounds in excess of dome pressure wasv necessary to maintain maximum eilciency. It is believed that with the present design the pressure can be slightly lower than this.

Throughout the periphery of the pressure portion of the working chamber (which roughly coincides in extent and position with the groove II2) there is no place where the oil has to flow through minute clearances more than a few millimeters in order to reach the point at whichv it eifectuates the seal. In most instances the movement ofthe oil is facilitated by the relative movement between the Acore I4 and the end walls. Thus, it will be observed that the groove II2 is closer to the periphery of the core I4 than the length of the eccentric movement of the core. As a result the movement of the core with respect to the end plates, even aside from the pressure, tends to wipe oil all along the zone between the groove II2 and the periphery of the core I4.

Another possible path of leakage for gas from the high pressure section to the low pressure section is around the blade I8. Of course, theends of the lblade have a sealed and stationary fit with the end walls and hence there will be no leakage across the ends of the blade. Apossible path would be radially inwardly of the blade around the innerside of the blade and radially outwardly of the blade to the other section. Another possible path would be in a, similar direction around the circumference of the rocker 16 or along the ends of the rocker 16 and around the blade I8. Any manner of getting suflicient oil across these paths will prevent leakage of gas along them. In the illustrated form of the invention the radial path inwardly of the blade is blocked by an oil channel I2I, seen best in Fig. 7, and the path around the circumference of the rocker is blocked by the oil channel |22. These two channels are connected together by one or more passages |23 drilled between them, and the channel |22 is connected by drilled one or more passages |24 with a passage |26 drilled vertically through the core and communicating with either or both of the grooves I I2. The paths along the ends of the rocker 16 are blocked by means of an extension |21 of the groove II2 formed on each end face of the rocker 16.

It will be observed fromFig. 2 that at the inner Side of the blade I8 a sealed pocket |28 is formed by the inner end of the slot 11. This pocket is preferably closed at its ends as seen in Fig. 1 because if oil were permitted to ow freely into this pocket it would be forced out of it by the blade I8, and this intermittent pumping might interfere with the pumping action of the oil pump.

which, as described below, is carefully timed. If

novent is provided for the pocket |28, there will of course be a partial vacuum therein when the blade I8 is in its retracted position as seen in Fig. 2. This partial vacuum has been found to be harmless in itself, however. It could only be objectionable by drawing in oil which would be trapped and cause an oil knock. If this should occur in any particular design, a hole may be drilled through the blade I8 to'vent the pocket |28 to the dome outside of the cylinder I3. Another way of venting pocket |28 is to provide one or more vent passages along blade I8 to the intake section of the pumping chamber. This tends to have an advantage of helping to fill said chamber byincreasing the vacuum thereof during the first half of the cycle and forcing gas back into it in the second half of the cycle. If no open vent for pocket |28 is provided and if it is found that too much oil gets into this pocket, an outlet for the oil may be provided with a check valve therein to prevent return of the oil. Such taken to minimize the seepage of oil thereto. To this end the oil grooves I I2 do not maintain their full width in the vicinity of the rocker I6 but are reduced in" width and positioned slightly outwardly from their positions elsewhere so as to keep them as far away from the pocket |28 as possible. Likewise, the extension |21 is quite thin. It will be observed that the grooves ||2 and |21 could connect with the channels |2| and |22, if the latter were extended, so that the passages |23 and |24 (Fig. 2) can probably be dispensed with. The joint between blade I8 and the end plates does not need sealing, but if it did, the

This oil tends to lbe thrown against the cylinder by centrifugal force and hence is squeezed into the line of tangency to seal the slight clearance between the core I4 and the cylinder I3. It may be noted, incidentally, that this same oil would help to seal the paths around the blade I8 since the reciprocating movement of the blade would tend to carry the oil into the slot 11, and the rocking movement of the rocker 16 would tend to carry the oil in between the rocker and the core I4.

Pressure of oil Both for sealing the end clearances and to provide oil in'the pumping chamber to seal the line of tangency, it is essential to have a little oil owing outwardly from the groove II2. The oil pressure, therefore, must be high enough to overcome the pressure in pumping chamberopposing its ow. Although it is dicult to determine what happens inside of the pump, it is believed that best sealing is obtained by having the iiow maintained throughout the pressure portion of the cycle. For this purpose it is desirable to have the oil pressure at all times during the pressure portion of the cycle higher than the momentary pressure in the pumping chamber. The maximum pumping chamber pressure is approximately the dome pressure, or pressure in the dome outside of the cylinder I3, plus theamount of pressure required to open the check valve 36. In other words, the maximum working chamber pressure,` during the discharge portion of the stroke, is always a certain slight amount higher than the dome pressure, or head pressure if a dome is not used.

With a positive displacement pump such as the tangential oil pump illustrated, very high pressures can be obtained. It may be objectionable to use these high pressures, however, partly because it consumes some energy to pump the oil at ,f high pressure and partly because a large quanoutlet could be provided through the end wall 48 tity of oil flowing into the pumping chamber is objectionable.

According to the present invention the pressure of the oil is automatically regulated to the proper value. This is accomplished by providing a re- Stricted pressure-relief vent |3| for the oil discharge system with the vent communicating with the dome so that it is exposed to dome pressure. Since the pump operates `at a relatively constant good seal because the oil would be forced throughl speed, the volume of oil discharged by the oil pump during eachcycle of the pumpwill be approximately uniform. The rate at which this oil, or a part of it, can flow through the relief vent |3| depends on the difference in pressure between the pressure on the oil and the dome pressure. Accordingly, with a given size of bore in the relief Vent the maximum oil pressure during each cycle will be ten pounds above dome. pressure. By making the opening a little larger, the maximum the clearances and held in the clearances until at least the very last portion of the cycle and of course its movement throughV the infinitesimal clearances is ylikely to be relatively slow as the oil pressure dies down. Nevertheless, the mainl tained pressure is believed to give an appreciably oil pressure during each cycle will be a little less above dome pressure; and by making the opening smaller, the maximum oil pressure during each cycle can be made any desired amount above dome pressure.

Although tests with a pressure gauge have indicated that approximately ten pounds above dome pressure is the optimum oil pressure, this figure is given merely for help in determining by empirical test the optimum pressure. It is certain that ten pounds will give fairly good results. The pressure required by each design of pump probably varies somewhat because of the distance that the oil may have to be forced through narrow clearances to effectuate the seal. As previously pointed out, the distances in this case are very short and quite uniform. As a result it isbelieved that a pressure slightly lower than that heretofore required will be sufficient. It will be observed that the restricted orifice |3| communicates with an enlarged passage so that only a small part of the vent system is thus restricted. This facilitates adjusting its size and also, by avoiding the friction of a long restricted passage, is believed to make the pressure more directly responsive to the dome pressure.

It will be observed that the gas in the pumping chamber is under a pressure greater than intake pressure during most of itsrevolution, probably at least three-quarters of the revolution. lThe clearances should beY sealed during the entire pressure portion of the cycle. One of the advantages of most rotary oil pumps is that they can deliver) oil during substantiatlly their entire cycle Whereas a reciprocating piston typecan only deliver oil during a little less than half of its cycle. A tangential type of rotary pump is particularly advantageous because its discharge volume is not uniform but varies during each cycle and the variation can be utilized advantageously. During the initial part of the pressure portion of the cycle the pressure in the working chamber is still below dome pressure, and hence the oil pressure need not be very great to accomplish the seal at this time. On the other hand, from somewhere around the middle of the cycle to the end of the cycle the pumping chamberpressure is maintained at its maximum, and an oil pressure above the dome pressure is therefore required.

According to the present invention the eccentric cam 82 of the oil pump has its eccentricity so positioned angularly with \respect to the position of tangency of Vthe main pump that the oil pump cycle lags behind the main pump cycle by a predetermined amount. At present a lag of 90 is preferred. This begins the supply of oil at approximately the time oil for sealing is required, namely at the beginning of the pressure portion of the main pump cycle. It also supplies a substantial quantity of oil throughout the later part of the cycle of the main pump. If the oil pump cycle were not lagging, its loil delivery would taper off to zero at approximately the end of the main pump cycle. This would still give at least a fairly better seal or at least to give it with a lower peak oil pressure and hence with greater eiiiciency.

Another expedient has been adopted in the present instance for maintaining adequate seal at the end of the main pump cycle. In this instance theviinal portion of the oil groove |I2 and its extension |21 is carried slightly closer to the periphery of the core I4 than the preceding portions of the groove H2 so that the oil has a slightly shorter distance to iiow to effectuate the seal. As previously mentioned, this shifting of the final portion of the oil groove also helps to keep it away from the pocket |28 so that less oil will escape into said pocket,

Dierentz'al speeds Although the-cylinder and core rotate together and although they make the same number of revolutions per minute, they are not at all instants rotating at the same speed. Referring to Fig. 5, it will be observed that cross marks |36 and |31 have been made `on the cylinder and core respectively, exactly even with one another. In Fig. 6, the cylinder has rotated 180, but it is seen that the cross marks are no longer beside one another. The cross mark |31 has lagged a substantial distance behind the cross mark |36. Thus, While the cylinder was rotating 180, the core was rotating a little less than will return to the adjacent positions there shown.

This time while the cylinder is rotating the core rotates a little more than 180. It is evident, therefore, that there is a differential angular movement or relative change of speed between the two pumping members during each cycle. This has important; consequences.

If the driving force were applied to the core, it must speed up the cylinder during every alternate half-cycle. This would be very objectionable. The cylinder is a. very eiiicient ywheel or, in other words, has so much momentum that it is hard to speed up. It is necessary for the cylinder to be one having very high momentum for several reasons. Being outside of the core, it is of larger radius than the core and the momentum increases as the square of the radius. Furthermore, it must be quite thick, both to withstand the high pressures within it and to hold the blade With suicient rigidity or house the rocker-if the blade is carried by the core). It is desirable that its outer surface be concentric with the axis and circular in planes perpendicular thereto, and this means that it should be the same thickness 4throughout as at the blade-receiving portion where maximum thickness is required. Furthermore, it carries the end plates Which not only addtheir own Weight to the mass and momentum of the cylinder, but also require a cylinder of substantial thickness for receiving the securing screws.

Because of this effective flywheel action of the cylinder, driving 'the core with the necessity of speeding. up the cylinder during alternate half-cycles would puta tremendous strain on all parts of the driving mechanism including the blade and the drive shaft. It is particularly bad because of the fact that the increase of force required to speed up the flywheel-cylinder coincides with the increase of force resulting from the first half of the compression of the gas. One of the features of the present invention, therefore, is to apply the driving force to the cylinder. f

Applying the driving force to the cylinder utilizes its flywheel action to full advantage since it rotates at a uniform rate of speed. The ilywheel effect of the core is relatively small and its change of speed therefore relatively unobjectionable. One reason for extending the bearing hubs 13 and 14 of the core is to provide adequate bearing surface with a slim shaft 24. The use of the slim shaft permits the core to be smaller than otherwise. Furthermore, the differential speed of the core with respect to the constantly driven cylinder is now somewhat advantageous. Instead of having the acceleration of the core coincide with the increase of pressure, the deceleration of the core coincides with the increase of pressure so that the core actually delivers some power to smooth over the load curve at the'time when it would otherwise have a relatively abrupt rise. This is best seen from a more detailed study of Figs; and 6.

In Fig. 5, it will be observed that the blade I8 is 90 beyond-the point of tangency. The high pressure section of the work chamber ahead of the blade I8 is still nearly full size. In Fig. 6, on the other hand, the blade has rotated 180 farther and the high pressure section of the work chamber ahead of the blade has been reduced to a very small size. It is evident, therefore, that most of the pumping is done during this half-cycle. It is during this same halfcycle that the cross mark |31 has lagged with respect to the cross mark |36. In other words, the core has lagged during the half-cycle corresponding to the major portion of the pumping operation.

The deceleration period is not exactly coincidental with the period of lag but is 90 in advance of it. Therefore, the deceleration period, when the core is giving up the energy in its momentum, is during the first half of the pumping cycle when the blade rotates from the point of tangency, where it is performing n'o work, to the point of maximum exposure where it is doing the maximum work. It is during this half cycle that the greatest change of compressional torque takes place. The giving up of energy by the core, therefore, serves to smooth over this increase of torque resulting from the compression.

Fromthe foregoing it is seen that it is very important to apply the driving connection to the outer cylinder rather than to the core, especially in larger pumps where the ywheel action and inertia effects are greatest. l The same considerations also increase the importance of having the blade rigid with the driven cylinder and extend at all times at least as far as the axis of the rocker. If both the cylinder and core were rotating uniformly at a constant speed, it would take very little force` exerted through the blade and rocker to rotate the core. Since the core is accelerated and decelerated during each revolution, however, there is a very substantial driving force exerted between the blade and the core. By having the blade extend to the axis of the rocker there is no danger that this driving force will cause a canting of the rocker and a binding action as a result thereof.

This same driving force exerted between the blade and the rocker also makes more desirable the provision of a rigid blade. To this end some interlocking engagement between the end plates and the inner pontion of the blade is desired. In the illustrated form of the invention this interlocking engagement is provided by means of dowels |4I.

It is not a simple matter to drive the cylinder in a way that is entirely satisfactory commercially. If the motor is mounted in the same' plane as the pump, the size of the motor makes it very expensive and relatively inefficient electrically. Even if the motor is mounted on a hollow bearing shank f the cylinder such as 51,

the motor is still undesirably large. Of course, an ordinary driving shaft could be connected to the cylinder head at one side and extended to the motor, but this introduces the dimculty of providing adequate bearing means for the core in order to prevent canting thereof. According to the present invention, as has already been described, fthis is accomplished in a very satisfactory manner by providing a stationary shaft on which the core is journaled with bearing shanks extending beyond the confines of the core to give Aadequate bearing surface. and by preventing a cantilever flexing of the shaft by supporting its projecting end with respect to the cylinder by means of the ball-bearing unit 1|, which engages an eccentric extension on the shaft 24. The bearing unit 1| is so close to bearing 51 that it could be deflected laterally only by shearing the shank of head 49.

Alternate bearing structure Another bearing structure which prevents relative canting of the pump members, and still permits driving the cylinder through a small drive shaft, is illustrated in Fig. 8. In this instance a motor |5| is enclosed within the dome |52, so that it is not necessary to have any moving parts extending out through the dome. This arrangement can, of course, be provided with the form of pump shown in Figs. 1 to 7. The base |53 of the dome also forms the base of an internal frame having side walls |54 and upper support member I 56. 'Ihe shaft |51, driven by the motor, extends downwardly through the upper support member |56, and into the bearing hub |58 secured rigidly to the base plate |53.

A heavy disc |6| is carried by the shaft |51, and is preferably integral therewith'for the sake of rigidity. The disc |6I forms the lower end Wall of the pump, and has a cylinder |62 rigidly secured thereto. The upper end wall |63 is rigidly secured to the cylinder |62. A bearing sleeve could be extended downwardly from the upper support plate |56 to cooperate with a hollow bearingl shank on the end plate |63, but in view of the rigidity of the disc |6I, and the fact that the shaft |51 gives bearing support for the disc |6| and the cylinder |62 at both sides thereof, it is believed that the additional bearing will be unnecessary.

The core |66 is journaled on a bearing sleeve |61 extending downwardly from the support |56.

The core |66 has an elongated bearing shank |66 to provide an adequate length of bearing for the core. Because the core is supported on both sides of its center, it is apparent that it cannot cant unless its bearing support fiexes. However, it is also apparent from Fig. 8 thatthe bearing sleeve |68 can appreciably ex, partly because of its rigidity as a sleeve of relatively large diameter inside of the sleeve |61.

ase/cari and partly because it is'reinforced very effectively by the shaft l51. As a matter of fact the compressional force within the pump would have to shear oi the shaft 51 at the disc itl in order to produce any canting between the cylinder and the core.

The thick disc ist lends itself admirably to an ideal intake arrangement. An intake passage iii may be drilled into the base and communicate with a chamber i12 into which the lower end of the shaft l? projects. This shaft has a bore i125 drilled therein, which communicates with a radial passage il@ in the disc iti. This passage in turn opens through a port to communicate with the intake section of the pumping chamber. With this arrangement of intake the intake port may be positioned fairly close to the vane, and may also extend nearly the fulllength or\height of the vane, if desired. Likewise it may open into the side of the intake section. A large intake port is advantageous in permitting the maximum quantity of gas to pass into the pumping chamber of the pump during each cycle. It is obvious that the intake passages throughout may be somewhat larger than they have been illustrated.

An oil pump' has been diagrammatically illustrated by the provision of a cylindrical recess it and a tangential rotor |82 forming a pumping chamber, which may be' divided by any Suitable blade structure. An oil intake has been diagram- `matically illustrated in dotted lines at |83, with the oil discharge likewise illustrated at ml. This discharge will communicate with a groove 88%, which in turn communicates with an oil passage |86. 'I'he oil passage |86 in turn communicates with an annular groove |81 in bearing sleeve |61. A passage through the sleeve |61 connects the oil groove |81 with another annular oil groove |88, to which is connected'a radial passage |69, which in turn communicates with the vertical bore |9|, corresponding to the vertical bore ||3 of Figs. 1 to 7. 'Ihe oil sealing grooves and passages of the core |66 maybe the rsame in all other respects as in Figs. 1 4to 7,-the passages |9| communicating with annular and radial grooves as in said figures.

A longitudinals groove |92, which may be a extent suitable. The disclosure of that application is hereby made a part of lthis application by reference.

From the foregoing it is seen that in spite of the failure of the prior art to provide a successful rotary couple compressor or gas pump, applicant has invented such a compressor which is highly satisfactory. The preferred illustrated forms meet all oi the requirements set forth in the first part of this speciiication. A pump of either oi these forms will be much more eicient than any comparable pump heretofore known, and will give extremely satisfactory service.

Although the preferred embodiments are especially Adesigned to meet the problems ci compressors (including vacuum pumps), the inventionin many of its aspects relates to other types oi" pumps. Furthermore, 'almost all features of the invention lare suitable for use with gaseous (steam) engines. The emciency -to be obtained in them by proper sealing has heretofore been overlooked.

Automatic unloading Some pumpsreduire expensive means for releasing the-gasesfrom. the cylinder when the driving .motor is starting in order to relieve the startingv load and let the motor get started. This is called unloading. No such special devices are required for the pump of the present invention. This function isautomatically provided .by the l'pressure relief-vent |3l or |911'. At the very slow spiral groove (though not so shown), provides lubrication for the length of the bearing on the A similar longitudinal groove |94 provides lubrication along the length of the outside of the bearing sleeve |61. An annular groove |96 communicates with the upper end of groove |94, and a. restricted pressure-relief vent |91 communicates with the annular groove |96,r serving the same purpose as the relief vent |3| in Figs. 1 to '1.

The angular displacement between the pump- .f

ing cycle of the oil pump |8|, |82, and the pumping cycle of the main pump may be the same as described with respect to Figs. 1 to 7', although for simplicity of illustration it has not been so shown.

- It will be recognized that Fig. 8. is very dia.-

grammatic, being intended, for the most part, to illustrate Vthe bearing arrangement and the lntake possibilities which it permits. Any details be considered to be the same as theyvare illusstarting Ispeecll the oil delivered by the oil pump has plenty of time to pass through this relief vent without causing the oil pressure to be much higher than dome pressure. It-may in fact be less thanv the pumping chamber pressure. Under these conditions an appreciable time is required for the'oll to ll up the clearances which naturally drain somewhat when the pump is stationary. During this appreciable time the motor can get started with relatively little load since the pumping chamber is inadequately sealed.

It should be noted that the use of effective oil sealing permits the clearance tolerances to be slightly greater than in prior pumps. ingly, lag in supplying oil constitutes a very effectiveautomatic unloading feature.

I claim:

-1. In 'a compressor, a gas-tight dome, pump members within the dome including 'a rotatable hollow. cylindrical member, a rotatable core member mounted therein in eccentric tangential relation, and end plates rigidly secured to one of said members to forni with the other member i elated with the compressor including a positive trat-.ed in application serias No. 185.830 to the displacement oil pump. an oil reservoir, andone o1 said clearance spaces, said pump having a discharge passage from which and by which oil is directly delivered in a substantially uninterrupted column to an intermediate portion of said one clearance-space, said pump operating to force oil 'intosald one clearance space at s. pressure in excess o! that within the dome, and means for returning excess'oil from said passages to the reservir.

2. In a compressor, a. gas-tight dome. pump 4hollow cylindrical member,

members within the dome including a rotatable hollow cylindrical member, a rotatable core member mounted therein in eccentric tangential relation, and end plates rigidly secured to one of said members to iqnxn with the other member a pump chamber, means dividing the chamber into intake and discharge sections with the lat-V ter communicating with'the dome, power means for producing relative movement between thel core member and the cylindrical member to produce a pumping action, said relatively movable pump members having infinitesimally small end clearances, a lubricating and gas sealing system associated with the compressor including a Ypositive displacement oil .pump within the dome, an oil reservoir, and one of said clearance spaces,v said pump being driven by said power means and having a plurality of discharge passages including one passage from which and by which oil is directly delivered to said one clearance space, said pump operating to force oil into said one clearance space at a pressure in excess of that within the dome, and means for returning excess oil from said passages to the reservoir.

3. In a compressor, a gas-tight dome, pump members within the dome including a rotatable a. rotatable core member mounted therein in eccentric tangential relation, and end plates rigidly secured to one of said members to form with the other member a pump chamber, means dividing the chamber into intake and discharge sections with the latter communicating with the dome, means for producing relative movement between the core member and the cylindrical member to produce a pumping action, said relatively movable pump said pump operating to deliver a substantially continuous flow of oil into said one clearance45 space at a pressure in excess of dome pressure.

4. In a compressor, a gas-tight dome, pump members within the dome including a'rotatable hollow cylindrical member, a rotatable core member mounted therein in eccentric tangential relation, and end plates rigidly secured to one of said members to form with the other member a pump chamber, means dividing thechamber into intake and discharge sections with the` latter communicating with the dome, means for pro-, ducing relative movement between the core member and the cylindrical member to produce a pumping action, said relatively movable pump m'embers having infinitesimally small end clearances, a lubricating and gas sealing system as sociated with the compressor including a positive displacement oil pump, an oil reservoir, and at least one of said clearance spaces, said pump having a plurality of discharge passages including one passage from which and by which -oil is directly deliveredAl in a substantially cbntinuous conilnedmass to said onev clearance space, said pump operating to force oiLin@ s`aid one clearance space at a pressure in excess of that within the dome, and means for returning excess oil 70 from said passages to the reservoir.

5. In a compressor, a gas-tight dome, pump members within the dome including a rotatable hollow cylindrical member, a rotatable core member mounted therein in eccentric tangential 75 relation, and end plates rigidly secured to vone of said members to form with the other member a pump chamber, -means dividing the chamber into intake and discharge sections with the latter communicating with the dome, means for producing relative movement. between the core,

member and the\cylindrical member to produce a pumping action, said relatively movable pump members having lniinitesimally small end clearances, a lubricating and gas sealing system asof said clearance spaces, said pump having a discharge passage from vwhich and by which oil is directly deliveredV to said one clearance space, said pump being constructed to deliver varia-ble quantities of oil at diilercnt periods in its cycle and operating to deliver a maximum quantity of oil into said one clearance space at a pressure in excess of dome pressure after the time when the compressor passes the middle of one cycle of operation, and means for returning excess o'il to the reservoir.

6. In a compressor, a gas-tight dome, pump members within the dome including a rotatable hollow cylindrical member, a rotatable core niember mounted therein in eccentric tangential relation, and end plates rigidly secured to one of said members to form with the other member a pump chamber. means including a vane rigidly fixed in one member and having rocking and sliding engagement with the vother for dividing the chamber into intake and discharge sections with the latter communicating with the dome, means for producing relative movement between lthe core member and the cylindrical member to producev a vpumping action, said relatively movable pump membershaving iniinitesimally small end rclearances, a lubricating and vgas sealing system associated with the compressor including a positive displacement oil pump, an oil reservoir,

` and at least one of said clearance spaces, said pump communicating with a plurality of discharge passages including one passage from which and by which oil is directly delivered to said one clearance space, said pump`perating to force oil into said one clearance space at a pressure in excess lof that within the dome, and

. means for returning excess oil from said passages to the reservoir. i

7. In a compressor. a gas-tight dome, pump mem-bers within the dome including a. rotatable hollow cylindrical member, a rotatable core member mounted therein in eccentric tangential relation, and end plates rigidly secured to one of said members to form with the other member a pump chamber, means dividing the chamber into intake and discharge sections with the latter communicating with the dome, means for producing relative movement between the core member and the cylindrical member to produce a pumping action, said relatively movable pump members having intlnitesimally small end clearances, a lubricating and gas sealing system associated with the compressor including a positive vdisplacement lubricant pump communicating with a plurality of discharge passages communicatingwith the said clearances and with the space in the dome, the passageways and said clearances representing in totality such a restric- 4tion to the flow of lubricant discharged by said pump that the lubricant pump operates to deliver 1 lubricant to said passageways to keep them lled with oil and to discharge lubricant into said ly continuous confined mass to an intermediate clearances at a pressure greater than the dome pressure.

8. In a compressor, a gas-tight dome, pump members within the dome including a rotatable hollow cylindrical member, a rotatable core member mountedI therein in eccentric tangential relation thereto, and end 4plates rigidly secured to one of said members to form with the other member a pump'chamber with the end plates closely adjacent to end walls of the other member with inflnitesimally small clearance spaces therebetween, means dividing the chamber into intake and discharge sections with the latter section communicating with the dome, means for rotating the pump members, a lubricating and gas sealing system associated with the compressor including a positive displacement oil pump having discharge passageways, one of which passageways communicates directly with one of the said clearance spaces, said passageways and clearance space representing in totality such a restriction to the flow of oil discharged by said pump that the oil pump operates to substantially continuously fill said one passageway and to discharge oil therethrough into said one clearance space at a pressure greater than dome pressure.

9. In a compressor, a gas-tight dome, pump members within the dome including a rotatable hollow cylindrical member, a rotatable core member mounted therein in eccentric tangential relation, and end plates rigidly secured to one of said members to form with the other member a pump chamber, meansdividing the chamber into intake and discharge sections with the latter communicating with the dome, means for producing relative movement between the core member and the cylindrical member to produce a pumping action, said relatively movable pump members having innitesimally small end clearances, a lubricating and gas sealing system associated with the compressor including a positive displacement oil pump, an oil reservoir, and at passages including one passage from which and,

by which oil is directly delivered in a-substantially continuous confined mass to said one clearance space, said pump operating to deliver oil to said one clearance space at a pressure sufficient to force oilinto said one clearance space and overcome, for at least a portion of a cycle of the compressor,A the pressure of the gas in the said compressor pump chamber opposing movement of the oil, and Ymeans. for returning excess oil to the reservoir.

10. In a compressor, a gas-tight dome, pump members within the dome including a rotatable hollow cylindrical member, a rotatable core member mounted therein in eccentric tangential relation, and end plates rigidly secured to one of said members to form with the other member a pump chamber, means dividing the chamber into intake and discharge sections with the latter communicating with the dome, means for producing relative movement between the core member and the cylindrical member to produce a pumping action, said relatively movable pump members having innitesimally small-end clearances, a lubricating and gas sealing system associated with the compressor including a positive displacement oil pump, an oil reservoir, and at least one of said clearance spaces, said pump communicating with a plurality of discharge passages including one passage from which and by which oil is directly delivered ina substantialportion of said one clearance space, said pump operating to deliver oil to said one clearancev chamber, means dividing the chamber into intake and discharge sections with the latter communicating with the dome, means for producing relative movement between the core member and the cylindrical member to produce a pumping action, said relatively movable pump members having innitesimally small end clearances, a lubricating and gas sealing system associated with the compressor including a positive displacement oil pump, and at least one of said clearance spaces, said pump communicating with a plurality of discharge passages including one passage from which and by which oil is directly delivered in a substantially continuous confined mass to said one clearance space, said pump op'- erating to deliver oil to-said one clearance space at a pressurefsucient to force oil into said one clearance space and overcome, for at least a portion of a cycle of the compressor, the pressure of the gas in the said compressor pump chamber opposing movement of the oil.

12. In a compressor, pump members including a rotatable hollow cylinder anda rotatable core molmted in eccentric tangential relation thereto, each being'rotatable about its own center, end plates closing the space between the members to form a pump chamber, a blade dividing the chamber into intake and discharge sections, the end plates and blade being rigidly secured to one of the members, the end plates having infinitesimal clearances with the other member, and the blade sliding in a rocker in said other member and having at least a portion extending at all times-at least to the pivotal axis of the rocker, means for driving the rigid a.;- sembly including the end plates and blade and through the blade driving said other member, bearings for one of said members on-both sides thereof and bearing means for the other member, and means for sealing and lubricating said infinitesimal clearances including a secondary pump producing a pressure in excess of the pump head pressure and supplying'oil under suf- 'Iicient pressure to fill said clearances adjacent plates closing the space between the members to form a pump chamber, a blade 'dividing the l chamber into intake and discharge sections, the end plates and blade being rigidly secured to one of the members with the blade having a sealing t with said member and the end plates, the

end plates having infinitesimal clearances with the other member, and the blade sliding in a rocker in said other member, means for driving the rigid assembly including the end plates and blade and through the blade driving said other member, and means for sealing and lubricating said, innitesimal clearances by supplying oil yunder sufficient pressure to ll said clearances clearances with the other member, and the blade sliding in a rocker in said other member, means for driving the rigid assembly including the end plates and blade and through the .blade driving said other member, and means for sealing and lubricating said infinitesimal clearances including a secondary pump producing a pressure in excess of the pump chamber pressure and supplying oil at suilicient pressure to'fill said clearances adjacent the pump chamber substantially throughout the circumference thereof and supplying oil to the surfaces of the rocker.

15. In a compressor, pump members including a rotatable hollow cylinder and a rotatable core mounted in eccentric tangential relation thereto, each being rotatable about its own center, end plates closing the space between the members to form a pumpfchamber, a blade dividing the chamber into intake and discharge sections, the vend plates and blade being rigidly Secured to one of the members, the end plates having innitesirnal clearances with the other member, and the blade sliding in a rocker in said other member and having' at least a portion extending at all times at least to the pivotal axis of the rocker, means for driving the rigid assembly including the end plates and blade and through the blade driving said other member, bearings for each of saidmembers on both sides thereof, and means for sealing and lubricating said innitesimal clearances including a secondary pump adapted to deliver oil to said innitesimal clearances in suiiicient quantity and at a pressure at least in excess of the pump head pressure to eiectively seal said clearances against gas leakage.

16. In a compressor, a gas-tight dome, pump members within the dome including a rotatable hollow cylinder and a rotatable core mounted in eccentric tangential relation thereto, each being rotatable about its own center, end plates having at least a portion extending at all times at least to the pivotal axis of the rocker, means for driving the rigid assembly including the end plates and Iblad and through the blade driving said other member, bearings for one of said members on both sides thereof and bearing 'means -for the other member, and means for sealing and lubricating said infinitesimal clearances including a secondary pump adapted to deliver oil to said infinitesimal clearances in sufficient quantity and at a pressure at least in excess of the dome pressure to eiectively seal said clearances against gas leakage.

17. In a compressor, a gas-tight dome, pump members therein including a rotatable hollow cylinder and a. rotatable core mounted in eccentric tangential relation thereto, each being rotatable about its own center, end plates closing the space between the members to form a pump chamber, a blade dividing the chamber into intake and discharge sections, the end plates and blade |being rigidly secured to one of the members, the end plates having infinitesimal clearances with `the other member, and the blade sliding in a' rocker in said other member and having a@ least a portion extending at all times at least to the pivotal axis of the rocker, means for driving the rigid assembly including the end plates and blade and through the blade driving said other member, bearings for one of said members on both sides thereof and bearing means for the other member restraining it from canting, and means for sealing and lubricating` said infinitestimal clearances including a secondary pump within the dome and having at least one portion rotating with a main pump member and adapted to deliver oil to said innitesimalclearances in suicient quantity and at a pressure at least in excess of the dome pressure to effectively seal said clearances against gas leakage.

18. In a compressor, an air-tight dome, pump members Within the dome including a rotatable hollow cylindrical memlber, a core member mounted therein in eccentric tangential relation for rotation about its own center, and end plates rigidly secured to one of said members and having innitesimally small end clearances with the other to form a pump chamber, means dividing the cham'ber into intake and discharge sections comprising a blade rigidly secured to the same member to which the end plates are secured and l having a sealed t' with said member and said end plates, said blade having a sliding and rocking engagement with the other member, means for driving the blade through one of the elements rigid therewith to produce a pumping action, bearing supports for the pump members, and for at least one of said pump members on both sides thereof at points vfarther apart than the width of the pumping chamber, a lubricating and gas sealing system associated with the compressor including means adapted to deliver oil t0 said infinitesimal end clearances in sufficient quantity and at a pressure at least in excess of dome pressure to effectively seal said clearances against gas leakage.

19. Ina compressor, a gas-tight dome, pump members therein including a rotatable hollow cylinder and a rotatable core mounted in eccentric tangential relation thereto, each being rotatable about its own center, end plates closing the space between the members to form a pump chamber, a blade dividing the chamber into intake and discharge sections, the end plates and blade being rigidly secured to one of the members, the end plates having infinitesimal clearances-wlth the other member, a rocker carried by said other member and the blade slidingv in said rocker and havi'ng at least a portion extending at alltirnes at least to the pivotal axis of the rocker, means for driving the rigid assembly including the end plates and blade and through the blade driving said other member,

bearings for one of said members on both sides thereof and bearing means for the other member restraining it from canting, and means for sealing and lubricating said infinitesimal Yclear-.sfV

' inder being substantially circular in all radial cross sections to minimize the air resistance to its rotation and being located above any liquid in the gas-tight dome. l

20. In a gas pressure device, expansion chamber means including a rotatable hollow cylinder member and a rotatable core member mounted inV eccentric tangential relation thereto, each being 'rotatable about its own center, end plates closing the space between the members to form an expansion chamber, a blade dividing the chamber into intake and discharge sections, the end plates and blade being rigidly secured to one of the members, the end plates having infinitesimal clearances with the other member, a rocker carried by said other member and the blade sliding in said rocker and having at least a part extending at al1 times at least to the pivotal axis of the rocker, a driving connection applied to the rigid assembly including the end plates and l blade and through the blade being' connected to said other member, bearings for the cylinder on both sides thereof, arid bearing means for the core Ymember preventing canting thereof, and means for sealing and lubricating said infinitesimal clearances including a pump producing a pressure in excess ofthe head pressure against which the gas pressure device is working and supplying oil to said clearances adjacent the expansion chamber throughout the circumference thereof.

21. In a compressor, pump members therein including a rotatable hollow cylinder anda rotatable core mounted in eccentric tangential relation thereto, each being rotatable about its own center, a rocker carried by said core, end plates rigidly secured to the cylinder and having infinitesimal clearances with the core to close the space between the members to form a pump chamber, a blade rigidly secured to the cylinder and having a sealed fit with the cylinder and epd plates, dividing the chamber into intake and dscharge sectionsl sliding in said rocker and .having at least a portion extending at all times at least as far as the pivotal axis of the rocker, means for driving the blade through one of the elements rigid therewith, a bearing for the cylinder at each side thereof, and bearing means f or the core on both-sides of the center thereof, and. adjacent to the sides thereof, supported with respect to the cylinder at both sides thereof indeoendently. and means for -seal-ing and lubrirating said infinitesimal clearances including a pump substantially within the confines of the main compressor, and having at least one porfion rotating with a pump member, supplyingA oil to said clearances at a pressure in excess of the pump head pressure. and supplying it to said clearances adjacent the pump chamber throughout the circumference thereof, and to'the surfaces of the rocker.

lation thereto, each being rotatable about its own center, a rocker carried by said core, end plates rigidly secured to thecylinder and having iniintesirnalv clearances with the core to close the space between the members to form a pump chamber, a blade rigidly secured to the cylinder and having a sealed fit with the cylinder and end plates, dividing the chamber into intake and discharge sections, sliding in said rocker and having at least a portion extending at all times at least as far as the pivotal axis of the rocker, means for driving the blade through one of the elements rigid therewith, a bearing for the cylinder at each side thereof, and bearing means for the core on both sides of the center thereof, and adjacent to the sideslthereof, and means for sealing and lubricating said infinitesimal.

` clearances including a pumphaving at least one 22. In a compressor, pump members therein including a rotatable hollow cylinder and a rotatable core mounted in eccentric tangential reportion rotating with a pump member, supplying oil to said clearances at a pressure in excess of the pump head pressure, and supplying it to said clearances adjacent the pump chamber substantially throughout the circumference thereof, and to the surfaces of the rocker.

23. In a compressor, an air-tight dome, pump members within the dome including a rotatable hollow cylindrical member, a core member mounted therein in eccentric tangential relation for rotation about its own center, and end plates rigidly secured to one of said members and having ininitesimally small end clearances with the other to form a pump chamber, means dividing the chamber into intake and discharge sections comprising a vane rigidlysecured to the same member to which the end plates are secured and a lubricating and gas sealing system associated with th'e compressor 4including means adapted to deliver oil to said infinitesimal end clearances in sufficient quantity and at a pressure at least in excess of dome pressure to effectively seal 7said clearances against gas leakage.

24. In a rotary pump, the combination of a frame including a sealed housing, pump members therein comprising a cylinder and a core, heads which close the ends of the cylinder and are fixed thereto and one atleast of which is detachable,l means for rotatably mounting said cylinder and core on the pump fr'ame in eccentric tangential relation, comprising bearing projections on one of said cylinder heads, axially alined bearings on the pump frame by which said projections are rotatably supported, the means for eccentrically mounting the core comprising bearing means infiexibly associated with at least one of said axially, alined bearings, a single blade rigidly fixed, to the pump cylinder and having flexible engagement with the core, means for rotating the pump members applied to the cylinder, the housingadapted to hold a body of lubricating oil in its lower portion below the rotatable cylinder, means for raising oil from said body and delivering it to the bearing surfaces of the core, to the bearing surfaces ofthe cylinder bearing projections and to the clearance spaces between the sides of the core and the tw'o cylinder heads, said rotatable pump members being provided with uid supply and discharge passageways which communicate with the pump chamber at opposite sides of the pump blade, means for directing fluid from outside of said housing to said supply passageway, and means for directing fluid from said discharge passageway outside of said housing.

25. In a rotary pump, the combination of a frame including a sealed housing, a primary pump including pump members therein comprising a cylinder and a core, heads which close the ends of the cylinder and are fixed thereto and one at least of which is detachable, means for rotatably mounting said cylinder and core on the pump frame in eccentric, tangential relation, comprising bearing projections on said cylinder heads, laxially alined bearings on the lpump frame by which said projections are rotatably supported, the means for eccentrically mounting the core comprising bearing means infiexibly associated with at least one of said axially alined bearings, a single blade rigidly fixed to the pump cylinder and having flexible engagement with the core, means for rotating the pump members applied to the cylinder, the housing adapted to hold a body of lubricating oil in its lower portion below the rotatable cylinder, means for raising oil from said body and delivering it to the bearing surfaces of the core, to the bearing surfaces of the cylinder bearing projections and to the clearance spaces between the sides of the core and the two cylinder heads, said rotatable pump members being provided with fluid supply and discharge passageways which communicate with the pump chamber at opposite sides of the pump blade, means for directing iluid from outside of said housing to said supply passageway, and means for directing fluid from said discharge passageway outside of said housing, said means for raising oil comprising an auxiliary pump the intake of which is independent from the intake of the said primary pump. l

26. A rotary couple iiuid pressure device in cluding as working members a cylinder and a cylindrical core within the cylinder in eccentric tangential relation thereto, each rotatable about its own center, and including la blade .and end plates rigidly secured to the cylinder in sealed relationship thereto and with the end plates sealed to the blade, a slotted rocker sealingly and iiexingly connecting the blade to the core in driving relationship, with the blade at all times extending at least as far as the axis of the rocker, a driving connection rigidly connected to the cylinder, bearing means for rotatably supporting the cylinder and the core and preventing them from chamber into intake and discharge sections having intake and discharge ports respectively, said blade being rigid with the end plates and the bers, and an oil pump drivenV by jsa'ic'lfactuatingl means and having an inlet port and one'or morej,`

discharge passages leading tothe'working clearances of the main pump for supplying-oil -to said working clearances at a pressure in excess of the head pressure against which the main pump is Y l operating, said oil pump beinfgrof the rotary type and being characterized by its ability to deliver oil to said working clearances at said pressures for more than half of the pumping cycle for thel main pump.

28. In a compressor, main pump members in cluding a rotatable hollow cylindrical member,

a rotatable core member mounted therein in cantine: with respect to one another or jointly comprising rigidly supported bearings for the working members at both sides thereof and including al stationary bearing support for the core extending from a xed memb'er inwardly through an end plate and extending at least beyond the center of the core and supported with respect to the cylinder at its inner end, a shaft rigid with the cylinder extending from one end plate through the core and journaled in the rigidly supported bearing beyond the core from said last named end plate.

27. In a compressor, main pump members including a rotatable hollow cylindrical member, a rotatable core member mounted therein in eccentric t'angential relation and end plates rigidly secured to one of said members to form with the other a pump chamber, a blade dividing the eccentric tangential relation and end plates rigidly secured to one of said members to form with the other a pump chamber, a blade dividing the chamber into intake and discharge sections having intake and discharge ports respectively, said blade being rigid with the end plates and the member to which the plates are secured and having a pivotal sliding fit with the other member,

actuating means for producing a pumping actionV with relative movement between said members, and an auxiliary pump including as pump members, a cylinder and a core in eccentric tangential relation thereto to form an auxiliary pump chamber and a blade for the auxiliary pump carried by one of the auxiliary pump members and engaging the other thereof and dividing said auxiliary pump chamber into intake and discharge sections, said auxiliary pump being actuated with the main pump by said actuating means to produce a pumping action with relative movement between the core and cylinder of the auxiliary pump, an intake for the auxiliary pump adapted to supply a lubricant thereto, and discharge passage means for delivering the lubricant from the auxiliary pump to the clearances between the members of the main pump, said auxiliary pump being characterized by'its positive displacement 'of lubricant through the discharge passage means in a sufllcient quantity and at a suiicient pressure in excess of the head pressure against. which the main pump is operating to effectively seal said clearances against gas leakage.

29. A rotary couple iluid pressure device including as working members a hollow cylinder and a cylindrical core Within the cylinder in eccentric tangential rel-ation thereto, each rotatable about its own center and including a blade and en-d plates rigidly secured to the cylinder in sealed relationship thereto and with the end plates sealed to the blade to form a partitioned pump chamber, inlet and outlet ports for said chamber, a slotted rocker sealingly and flexingly connecting the blade to the core in driving relationship with the blade at all times extending at least asfar as the axis of the'rocker, an axial drive shaft rigidly connected to one side of the cylinder, and bearing mean-s for rotatably supporting lthe cylinder and the core and preventing them from canting with respect to one another or jointly, .said bearing means including bearing supports on opposite sides of the cylinder for rotatably supporting the cylinder, 'a center shaft extending inwardly from the side of the cylinder which is opposite the iirst named side thereof through at least a portion of the core to provi-de a. bearing for the core, said core being extended axially in at least one direction beyond the confines of the pump chamber to provide a core bearing surface on the center shaft that is substantially greater than the width of the pump chamber.

30. A rotary couple iiuid pressure device including as working members'a hollow cylinder and a cylindrical core Within the cylinder in eccentric tangential relation thereto, each rotatable about its own center and including a blade and end plates rigidly secured to the cylinder in sealed relationship thereto and with the end plates sealed to the blade to form a partitioned pump chamber, inlet and outlet ports for said chamber, a slotted rocker sealingly and iiexing- 1y connecting the blade to the core .in driving relationship Lwith the blade at all times extending at least as far as the axis of the rocker, an axial drive shaft rigidly connected to one side of the cylinder, and bearing means for rotatably supporting the cylinder and the core and preventing them from canting with respect to one another or jointly, said bearing means including bearing supports on opposite sides of the cylinder for rotatably supporting the cylinder, a center shaft extending inwardly from the side of the cylinder which is opposite the iirst named side thereof through the core to provide a bearing for the core, said core being extended axially in at least one direction beyond the confines of the pumpchamber to provide a core bearing surface on the center shaft that i's substantially greater than the Width of the pump chamber, said center shaft having anV extension concentric with the cylinder and extending beyond the confines of the pump chamber, and bearing means directly between said extension and means rigid with the cylinder.

31. A rotary couple uid pressure device in cluding as working members a hollow cylinder and a cylindrical core within the cylinder in eccentric tangential relation thereto, each rotatable about lts own center and including a blade and end plates rigidly secured to thecylinder in sealed relationship thereto and with the end plates sealed to the blade to form a partitioned pump chamber, inlet and outlet ports for said chamber, a slotted rocker sealingy and flexingly connecting the blade to the core in driving relationship, an axial drive shaft rigidly connected to the cylinder, bearing means for rotatably supporting the cylinder and the core and preventing them from canting with respect to one another or jointly, said bearing means including at least one outboard bearing for the cylinder and an axial bearing support for the core of greater length than the width of the pump chamber, said core being extended axially in at least one direction beyond the lateral confines of the pump chamber to provide a bearing surface cooperating with said bearing support to form a bearing that is substantially greater in extent than the width of the pump chamber,

able about its own center and including a blade and end plates rigidly secured to the cylinder in sealed relationship thereto and With the end plates sealed tothe blade to form a partitioned pump chamber, inlet and outlet ports for said chamber, a' slotted rocker sealingly and exingly connecting the blade to the core in driving relationship, an axial drive shaft passing through the core and one end plate and being rigidly connected to the other end plate of the cylinder, bearing means for rotatably sup-porting the cylinder and the core and preventing them from canting with respect to one another or jointly, said bearing means including at least one outboard bearing for the cylinder and an axial bearing support for the core of greater length than the width of the pump chamber, said core being extended axially in at least one direction beyond the lateral confines of the pump chamber to provide ay bearing surface cooperating with Isaid bearing support to form a bearing that is substantially greater in extent than the width of the pump chamber, said axial bearing support for the core comprising a sleeve bearing internally engaging the drive shaft and externally constituting a part of the core bearing.

33. A rotary couple fluid pressure device including as working members a relatively heavy hollow cylinder and a relatively light cylindrical core mounted within the cylinder in eccentric tangential relation thereto, each rotatable about its own center and including a blade and end plates rigidly secured to the cylinder in sealed relationship thereto and with the end plates sealed to the blade to form a partitioned pump chamber, inlet and outlet ports for said chamber, a slotted rocker sealingly and flexingly connecting the blade to the core in driving relationship with the blade, an axial drive shaft rigidly connected to the cylinder, bearing means for rotatably supporting the cylinder and the core and preventing them from canting with respect to one another or jointly, said bearing means including at least one outboard bearing for the cylinder and an axial bearing support for the core of greater length than the width of the pump chamber, said core being extended axially in at least one direction beyond the lateral` confines oi the pump chamber to provide a bearing surface cooperating with said bearing y support to form a bearing that is substantially greater in extentY than the width of the pump chamber, and driving means driving said cylinder and through the blade driving the core with non-uniform speed, the pump arrangement being such that the decelerationy of the core occurs during a period when the compressional toroue reaction on the blade is increasing whereby the greater mass of the cylinder as compared to that of the core taken in conjunction with the relationship between the deceleration period of the core and the increase in the compressional torque reaction on the blade tends to counteract 'the non-uniform rotation of the core and reduce vibration in the pump.

34. In a compressor, pump members including a rotatable hollow cylinder and a rotatable core mounted in eccentric tangential relation thereto, each being rotatable abo-ut its o'wn center, end plates/closing the space between the members to form a pump chamber, a blade dividing the chamber into intake and discharge sections, the end plates and blade being rigidly secured to one of the members, the end plates having infinitesimal clearances with the other member, and the blade sliding in a rocker in said other member and having at least a portion extending at all times at least to the pivotal axis of the rocker, means for driving the rigid assembly including the end plates and blade and through the blade driving said other member, bearings for one of said members on both sides thereof and bearing means for the other member, and means for sealing and lubricating said infinitesimal clearances including a secondary pump producing a pressure in excess of the pump chamber pressure and supplying oil under sufficient pressure to fill said clearances adjacent the pump chamber substantially throughout the circumference thereof -and supplying oil to the surfaces of the rocker, the aforesaid bearings and bearing means being supported by a structure in whichall joints affecting the alignment of the bearings and bearing means are metal to metal joints. i

35. Ina compressor, an air-tight dome, pump members within the dome including a rotatable hollow cylindrical member, a core member mounted therein in eccentric tangential relation for rotation about its own center, and end plates rigidly secured to one of said members and having innitesimally small end clearances with the other to form a pump chamber, means dividing the chamber into intake and discharge sections comprising a blade rigidly secured to the same member to which the end plates are secured and having a sealed fit with said member and said end plates, said blade having a sliding and rocking engagement with the other member, means for driving the blade through one of the elements rigid therewith to produce a pumping action, bearing supports for the pump membersand for Iat least one of said pump members on both sides thereof at points farther apart thanthe width of the pumping chamber, a lubricating and gas sealing system associated with the compressor including means adapted to deliver oil to said infinitesimal end clearances in suflicient quantlty and at a pressure at least in excess of dome lpressure to effectively sea1` said clearances against gas leakage, the bearing supports for the pump members being held in rigid invariable relationship to each other by structure which includes a part of the dome and an additional4 frame member within the dome having a metal to metal vengagement with the dome.

36. In a rotary pump of the class described, a sealed casing, a pump unit in the casing comprising an oil pump having a stationary outer cylinder, a gas pump having a rotatable outer cylinder and an electric motor rotor all rotatable on a common vertical axis with the latter two surmounting the oil puinp, a quantity of oil in the casing sufficient to rbring the oil level high enough to render the oil pump promptly effective to deliver oil directly to the gas pump on starting but not sufficient to submerge a substantial part of the rotating cylinder of the gas pump, said gas pump including a rotor eccentrically mounted in tangential relation with the cylinder and having a vane extending between the rotor and the cylinder to divide the crescent-shaped space between the rotor and the cylinder into intake and discharge stages, and means for driving the gas pump from the electric motor ro.. tor, said oil pump |being constructed and arranged to deliver oil' to thegas pumpl at a pressure greater than the pressure in the casing.

3'7. In a rotary pump or the like, pump members comprising a cylinder1 a piston mounted in the cylinder in eccentric tangential relation thereto, end walls rigidly secured to one of the pump members to form with the other a pump chamber, a vane rigidly held between the end walls and fixed to said one member sliding in a rocker in the other pump member and having sealed engagement with the end walls for dividing the work chamber between the pump members into intake and discharge sections, said sections having inlet and outlet ports respectively, means for rotating the pump members for producing a pumping action between them, and an oil pump and conduits for delivering oil at a pressure higher than the pressure of discharge from the work chamber to the clearances between the end Walls and the cylinder and to the sliding surfaces of the vane and the rocker, including a groove extending substantially throughout the circumference of each of said clearance spaces approximately as close to the work chamber as the difference between the diameterof the piston and the diameter of the cylinder.

38. The method of sealing a rotary gas pressure device having relatively shiftable working elements including a cylinder and a piston mounted eccentrically and tangentially within Y the cylinder and, with the cylinder, defining a Working space, which consists in delivering continuously between the engaging end surfaces of the piston and cylinder elements a liquid sealing medium at a pressure in excess of the maximum pressure developed Within the working space'of the device, and controlling the pressure of the liquid so delivered with respect to the pressure of the workingspace at different stages of operation to maintain a sealing pressure just sufficient to prevent escape of the work medium between the engaging surfaces while substantially avoiding penetration of more liquid sealing medium into the working space than is necessary to seal the point of tangency.

39. A rotary couple fluid pressure device including as Working members a cylinder and a cylindrical core within the cylinder in eccentric tangential relationthereto, each rotatable about its own center, and including a blade and end supporting the cylinder and the core and preventing them from canting with respect to one another or jointly comprising rigidly supported bearings for the working members at both sides thereof and including a stationary bearing support for the core comprising a sleeve extending from a fixed member inwardly through an end vplate and extending at least beyond the center of the core and supported with respect to the cylinder at its inner end, a shaft rigid with the cylinder extending from one end plate through the core and journaled in the rigidly supported bearing beyond the core from said last named end plate, said sleeve having an internal bearing surface engaging the shaft andan externalbearing surface constituting at least apart of the core bearing.

40. In a rotary pump of the class described, a sealed casing, a pump unit in the casing comprising an oil pump having a stationary outer cylinder, a gas pump having a rotatable outer cylinder, and an electric motor rotor all rotatable on a common/vertical axis with-the latter two surmounting the oil pump, a quantity of oil in 

